Subject: [Hipsec] RE: About the HIP security model (was Re: New multi6 draft: WIMP)

From: [email-masked] (Ayyasamy, Senthilkumar (UMKC-Student))
Date: Mon Feb 16 04:26:00 2004

>> the incentive to use such schemes? Although, crypto puzzles work
>> against intruders, are we not penalizing a legitimate user by asking
>> him to waste his CPU cycle?
>
> In other words, you raise the bar for DoS attackers, by slightly 
> penalizing legitimate users.  
  
IMO, HIP is a great choice for mobility/wireless scenarios( otoh, it has
to depend on something else for providing reliability.) But, one cannot 
expect a PDA/mobile device to burn cycles for solving the puzzle. In a 
wired-cum-wireless case, wired nodes are better placed than wireless 
nodes ( wrt CPU cycles.) Also, imagine a scenario where an attacker has
high CPU power and a legitimate user on a low end system. So, I would
expect the puzzle to vary depending on the CPU power (i.e. if high CPU 
power...it should solve fast.) I did see a work by MSR Penny Black folks 
addressing this aspect.

>> btw, is their any standardized RFC supporting weak authentication
>> methods?
> 
> My understanding of "weak" authentication is that the whole
> area is pretty new.  In fact, it looks like that we launched
> the term in our paper a couple of years ago:
 
The term is introduced by your paper. But, it is pretty common to see
research works in ad-hoc networks using weak authentication scheme. 
e.g., Ross Anderson's Resurrecting Duckling model. But, i agree, the 
security protocol 2002 survey paper is the widely cited one. I was 
just curious to know about IETF related works using weak authentication. 
thanks to both you and jari for the detailed replies. 
 
I would respond for the remaining parts of the mail after reading the 
HIP arch draft.

---

From: [email-masked] (Pekka Nikander)
Date: Mon Feb 16 04:45:01 2004

> ... So, I would

We did consider Mike Burrow's memory bound functions about
a year ago, after their publication at NDSS.  However, the
general feeling was that they were too new (too little analysis)
and too unclear from IPR point of view.  Hence, the decision
back then was to use SHA-1 for now.  Of course, the decision
can be reversed if it becomes clear that the memory bound
functions (or some other form of puzzles) works better, and
is sufficiently IPR free.

--Pekka N.